Structural, morphological, and optical properties of Co‐ substituted Zn2SiO4 nanopowders prepared by a hydrothermal-assisted sol-gel process

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Cobalt-substituted zinc orthosilicate pigments were obtained by pyrolysis of precursors synthesized by a convenient hydrothermal-assisted sol-gel process without using any toxic or expensive chemical (e.g., silicon alkoxides). XRD investigation confirms that the Co2+ ions are successfully incorporated into the Zn2SiO4 crystal. Rietveld refinement data reveals that unit-cell parameters increase with Co-content in Zn2-xCoxSiO4 solid-solutions. The homogeneous pigments are composed of largely agglomerated primary particles having a size less than 70 nm. The UV–visible spectroscopy shows that the blue color of pigments is caused by the presence de Co2+ in tetrahedral sites of Zn2+. The colorimetric parameters indicate that a blue pigment could be achieved with the only x = 0.05. A content of less than 5 wt% of the prepared pigments gives a deep blue hue to ceramic glazes. Cobalt-substituted Zn2SiO4 pigments exhibit high coloring performance and a relatively less cobalt content, which make them promising pigments for ceramic tiles.